Wikipedia:Styletips/9

Unit symbols: spacing

Values and unit symbols are separated by a space (preferably a non-breaking space):
 * Correct: 5 min, 3 lb, 90 &deg;C
 * Incorrect: 5min, 3lb, 90&deg;C

Only angular and coordinate degrees, and the percent sign, are unspaced:
 * 90&deg; (a right angle), 76%

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